Experimental autoimmune uveitis (EAU) is induced by immunization of rats and other experimental animals with S-antigen (a soluble antigen from the retina) is being investigated in this laboratory as a model of human intra-ocular inflammation. This experimental inflammation can be transferred from donor rats to naive recipients using lymphocytes harvested from the spleen or lymph nodes. Following harvesting of the cells from the donors and three days in culture with stimulating antigen, the cells are injected into the intra-peritoneal cavity and five to seven days later the recipient rats develop EAU. The mechanisms of transfer of disease is unclear. This work has used radioactively labeled lymphocytes to determine the fate of these lymphocytes after injection into the peritoneal cavity and during the process of the development of uveitis. The goal of this project is to understand the initiating mechanisms of inflammation in the hope that these mechanisms can be extended and applied to human inflammations. Thus far we have determined that only a small percentage of the lymphocytes injected into the peritoneal cavity actually reach the eye during the induction of EAU. Of 100 million cells transferred into the peritoneal cavity, approximately 5,000 reach the eye. Many more reach the spleen, liver and thymus however. Further studies of the time course and type of cell reaching the inflammed eye are in progrsss with the goal of understanding the relationship between donor and host lymphocytes in EAU.